This invention relates to devices used for the treatment of waste water. More specifically, this invention relates to a pump and filter system used for the filtering of liquid effluent contained in a septic tank.
Waste water discharged from commercial or residential property contains both liquid and solid wastes which are typically collected in a waste water collector, such as a septic tank. In such septic tanks, the liquid and solids are generally distributed into three layers: an upper horizontal scum layer, a lower horizontal sludge layer, and a relatively clear, horizontal effluent layer located between the two other layers. During operation of these septic tanks, liquids from this horizontal effluent layer are intermittently discharged from the septic tanks. During such discharge the solids contained within the septic tanks are preferably retained in the septic tanks to be decomposed during the normal operation of the system. Intermittently, the septic tanks are cleaned to remove any excess solids contained therein.
During normal operations, some solids become mixed into the relatively clear horizontal effluent layer. These solids often migrate into this layer on gas bubbles produced during decomposition of solid material contained in the lower sludge layer. These solids will be discharged with the effluent if not filtered out of the effluent. Excess solids discharged with the effluent may gradually degrade the effectiveness of the entire septic system.
To reduce the likelihood of discharge of solids from the septic tank, a number of different types of filtering devices for the liquid effluent have been developed. For example, cylindrical mesh screen filtering systems which surround a gravity flow outlet system and discharge pump are disclosed in U.S. Pat. Nos. 5,207,896 and 4,439,323.
The effluent flows into the filtering system generally through openings in the side walls of the filter system which are designed to match up with the relatively clear, horizontal effluent layer. For example, the devices of U.S. Pat. Nos. 5,492,635 and 4,439,323 utilize a plurality of openings in the walls of the filtering system with these openings designed to be placed within the relatively clear, horizontal effluent layer.
Other devices placed within a septic tank which use a filtering system different from a mesh screen are disclosed, for example, in U.S. Pat. Nos. 5,482,621 and 5,382,357. These patents disclose filtration of the effluent using a specific flow pattern for the effluent through an open bottom of a filter element, out the sides of the filter element through an annular space adjacent to the filter element, and finally to a discharge opening of the device for discharging filtered effluent from the septic tank.
Other systems for filtering solids from the effluent of a septic system utilizing a stacked disk dam system as the filtering system are disclosed in U.S. Pat. Nos. 5,582,716, 5,207,896, 4,710,295, 3,332,552 and 2,900,084. See also U.S. Pat. No. 5,264,120 which utilizes both a mesh screen and a disk dam system to filter the effluent. See also U.S. Pat. No. 5,690,824 which utilizes a series of stacked mesh filters.
U.S. Pat. No. 5,591,331 discloses a different filtering system comprising a plurality of vertically extending removable side walls, each of which contains a filtering screen for filtering the effluent.
A filter system containing a removable filter with diagonal slits for filtering effluent present in a septic system is disclosed in U.S. Pat. No. 5,569,387.
In addition to systems which utilize a single filter element within a filter system, multiple filter element systems for filtering effluent in a septic system are disclosed in U.S. Pat. Nos. 5,580,453 and 5,492,635. Each of these patents mandates a specific flow pattern for the effluent entering the filter system and exiting through a discharge opening in the housing of the filter system.
Because of limitations on the flow of the effluent through these systems, problems may arise from clogging of the filters which necessitates frequent cleaning of these systems. In addition, some of the screen filter systems can collapse even in normal use, also necessitating cleaning and/or replacement.
Thus, a need exists for a more effective system for filtering solids from the effluent of a septic system which overcomes the problems present in prior art systems.
Accordingly, it is an object of this invention to disclose a pump and filter system for filtering effluent present in a waste water system.
It is a further object of this invention to disclose a pump and filter system utilizing a tubular element containing an opening which is in communication with the relatively clear, horizontal effluent layer, which opening permits the effluent to flow into the pump and filter system.
It is a further object of this invention to disclose a pump and filter system for filtering effluent from a waste water system where the filter system contains a significant amount of filtering surface, thus reducing the likelihood of clogging of the filters during normal operation.
It is a further object of this invention to disclose a pump and filter system containing multiple filter elements which are easy to clean and replace.
It is a further object of this invention to disclose a pump and filter system where the pump is located adjacent to the filter elements.
It is a further object of this invention to disclose a shoulder seal secured within the filter housing which supports a filter element holder for the filter elements and which seals the filter element holder and filter elements in place within the pump and filter system.
It is a further object of this invention to disclose a check valve located in the bottom of the filter housing which when opened permits accumulated particulates within the pump and filter system to be flushed out of the system.
These and other objects and features of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description, along with the accompanying drawings, provides a selected example of construction of the device to illustrate the invention.